FULL-SCALE TESTS ON APU NOISE REDUCTION

摘要

The present paper describes an experimental investigation of the noise emission of a full-scale Garrett (Honeywell) GTCP 36-300 APU as installed on commercial airplanes like the Airbus A320. The APU exhaust noise emissions are measured in a well-controlled environment by 25 ground-based microphones arranged in a polar arc. Comparing a hard-wall reference case with different exhaust mufflers, special attention is given to the assessment of the noise reduction obtained. The performance of a newly designed muffler is compared to the standard device for the most relevant operating states ECS (environmental control system) and MES (main engine start). The paper concludes with a short examination of possibilities to improve the overall noise reduction.